Intake manifold

ABSTRACT

A bolt-on replacement intake manifold has an asymmetrical plenum with a first end including an inlet, a closed terminal end, a concave top surface and a convex bottom surface; a flange; and a plurality of runners extending from the bottom surface of the plenum and terminating at the flange. The plenum defines an interior space in flow communication with the runners. The bottom surface of the plenum is wider than the top surface. The plenum initially widens from the inlet to the first runner and then begins to narrow from the first runner toward the last runner adjacent to the closed terminal end. The runners are tapered, curved, and vary in length. The intake manifold causes air to exit each of the plurality of runners at substantially the same angle. The manifold balances airflow across each runner and increases swirl inside the cylinders enhancing fuel economy, power output, and torque.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/194,911 filed on Mar. 3, 2014.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to components for internalcombustion engines and more particularly to an intake manifold for useon high output engines including diesel engines found on semi-trailertrucks.

2. Description of Related Art

It is well established that power and torque output are of utmostimportance in the field of semi-trailer and semi-tractor trailer truckengines. Certainly in many instances power and torque are maximized atthe expense of fuel economy. However, with the onset of ever-increasingfuel costs, efficiency has been brought to the forefront oftractor-trailer technology. As many tractor-trailers have an averageoperational life expectancy exceeding ten (10) years, there is adefinite need to find ways to increase the efficiency of existing enginedesigns. Indeed, newer and more efficient engine designs are always inthe pipeline, but it is not always the most economical solution to swapout equipment or send otherwise reliable and durable tractor-trailerengines to end-of-life.

Diesel engines have long been known to provide greater torque and oftenbetter fuel efficiency than gasoline engines. Generally speaking, adiesel engine, also known as a compression-ignition engine, is aninternal combustion engine that uses the heat of compression to initiateignition and burn the fuel that has been injected into the combustionchamber. This contrasts with spark-ignition engines such as a gasolineengines that use a spark plug to ignite an air-fuel mixture. Ignitioninside a diesel engine is achieved when one or more pistonsreciprocating inside a cylinder physically compresses air introducedinto the cylinder to the point where the air reaches a high enoughtemperature to ignite vaporized diesel gasoline injected into thecylinders. The vaporized fuel then combusts and drives the pistonoutward from the cylinder, supplying power to the crankshaft.

Generally speaking, the higher the compression ratio of the engine, i.e.the ratio between the volume of the cylinder at its largest capacity tothe volume at its smallest capacity, the more efficient the engine.Because diesel engines do not have fuel in the cylinder beforecombustion is initiated, a large amount of air can be loaded in thecylinder without pre-ignition and therefore higher compression ratioscan be achieved as compared to gasoline engines. As having more air inthe cylinders allows more fuel to be burned at a more efficient rate,optimizing the volume of air in the cylinders is the key to unlocking adiesel engine's efficiency and power.

Many solutions for maximizing air flow into the cylinders have beenused, such as superchargers and turbochargers (or combinations of thetwo) but there has not been much thought put into the actual air intakemanifolds of the these engines. Traditional intake manifolds for dieselengines, particularly those used on tractor-trailer engines, such as theVolvo D13 motor, comprise a rudimentary “shoe box” design, shown inFIG. 1. These intake manifolds have a basic box-shaped plenum with anair inlet and an open bottom in flow communication with a cylinder headin which the cylinders and cylinder valves are seated. Typically theinlet of the intake manifold is in flow communication with anintercooler that receives compressed or “forced” air from atuborcharger. Such a design is prone to significant flow and pressurelosses and substantial variance in airflow and pressure from onecylinder to the next as inlet air tends to collect at the rear end ofthe plenum, causing more air to enter the cylinders at the rear leadingto a leaner fuel/air ratio as compared to the cylinders toward the frontof the plenum, which receive less air and therefore have a richerfuel/air ratio. An imbalance in airflow rates and in turn cylinderpressure causes an uneven distribution of power across the cylindersleading to decreased overall efficiency, power output, and fuel economyas the “richer” cylinders in effect pull the “leaner” cylinders aroundthe crank shaft. Accordingly, there is a need in the art for an improvedbolt-on replacement intake manifold design, particularly useful forlarge diesel engines, that provides measurably increased efficiency andfuel economy by correcting the imbalance of air flow rates and pressureacross the cylinders.

Several attempts have been made to design intake manifolds that increasepower and output, however none are sufficiently engineered to overcomethe existing problems with manifolds for large diesel engines.

For example, U.S. Pat. No. 7,073,473 to Boyes describes a tunable intakemanifold for directing a flow of air between a plenum and an internalcombustion engine. The tunable intake manifold includes a manifoldhousing defining an interior. The manifold housing has a plurality ofrunner walls extending through the interior. The tunable intake manifoldalso includes a slider having a slider wall having an angled portionseparated from a primary portion by a curved portion. The slider wallextends through the interior of the manifold housing. The slider wallcooperates with the runner wall to define a runner having a definedcross sectional area for transporting the flow of air therethrough. Theslider is slidably engaged with the manifold housing for moving theslider wall relative to the runner wall to selectively change thedefined cross sectional area of the runner, such that the volume of airpassing therethrough changes with the movement of the slider. The angledportion of the slider travels parallel to the runner wall at atransmitting end of the runner.

U.S. Pat. No. 6,571,760 to Kallander describes an intake manifoldcomprising a first end, an opposing second end with an end wall, and atleast a first internal wall, if the body of the air inlet manifold has acircular cross-section. Alternatively, the air inlet manifold body has arectangular cross-section, with several internal walls. The air inletmanifold extends in a longitudinal direction from the first end to thesecond end. The air inlet manifold has an air inlet at the first end andat least one distribution chamber for air extending along thelongitudinal direction and restricted by at least the first internalwall. The air inlet manifold also has at least one air pipe for eachcylinder. The pipes are distributed along the longitudinal direction.The pipes or runners protrude perpendicularly from the manifold. For atleast one of the pipes, a profile between the first line and the secondline located proximate to the air inlet has different curvature than aprofile between the first line and the second line located distant fromthe air inlet. The profiles may advantageously be in the form ofcurvatures and the first area is preferably greater than the secondarea. Preferably, the profile between the first line and the second linelocated proximate to the air inlet has a greater curvature than theprofile between the first line and the second line located distant fromthe air inlet, and preferably the first area is greater than the secondarea.

U.S. Pat. No. 5,005,532 to Shillington describes a manifoldcharacterized by a plenum surrounded by runners that spiral around theplenum sidewall to the entrances to the engine cylinders. Thecircumferential extent of each runner exceeds 360 degrees about alongitudinal axis of the plenum.

Japanese Patent JP2003074357 to Mamisa describes an intake manifoldhaving a plurality of intake branch passages for distributing intake airfrom an intake collecting part of an intake manifold to the respectivecylinders. The branches or runners have bend portions bent toward thecenters of the respective related cylinders, on an intake branch passageside of connection portions to intake ports on a the cylinder head. Abend portion connected to a cylinder more distant from anintake-introducing portion of the intake collecting part has a largercurvature. This manifold is designed for gasoline engines and providestwo runners per valve in a complex configuration.

It is, therefore, to the effective resolution of the aforementionedproblems and shortcomings of the prior art that the present invention isdirected. However, in view of the intake manifolds in existence at thetime of the present invention, it was not obvious to those persons ofordinary skill in the pertinent art as to how the identified needs couldbe fulfilled in an advantageous manner.

SUMMARY OF THE INVENTION

The present invention provides an intake manifold configured to improvethe overall fuel efficiency, and power and torque output of an internalcombustion in engine. In some embodiments, the intake manifold comprisesan asymmetrical plenum having a first end including an inlet, a closedterminal end, a top surface and a bottom surface; a flange; and aplurality of runners extending from the bottom surface of the plenum andterminating at the flange. The plenum defines an interior space in flowcommunication with the runners. The bottom surface of the plenum iswider than said top surface and, in some embodiments, the cross-sectionof the plenum has a rounded triangular shape. In some embodiments, thetop surface is concave and the bottom surface is convex. The plenuminitially widens from the inlet to the first runner and then begins tonarrow from the first runner toward the last runner adjacent to theclosed terminal end. With this configuration, the intake manifold causesair to exit each of the plurality of runners at substantially the sameangle.

The asymmetrical shape of the runner causes air to initially slow downas it enters the inlet, allowing time for air to enter the first fewrunners without racing by. Further, the top to bottom taper of theplenum creates a pressure differential across the plenum, with higherpressure at the top and lower pressure toward the entry of the runnerswhich forces air out from the plenum and through to the runners. In someembodiments, the runners are tapered from the plenum toward the flange,are curved, and vary in length to promote air to exit the runners atsubstantially the same angle. Additionally, an interior aspect of therunners is radiused where the runners meet the bottom surface of theplenum.

The manifold is configured to bolt-on to a cylinder head at the flange,placing each of the runners in flow communication with a respectiveconduit of the cylinder head. The manifold is effective to balance theairflow rates across the runners and also provides an optimal angle ofair entry into the cylinder head to increase swirl inside the cylinders.The improved airflow balancing and swirl cause a cleaner and moreefficient fuel burn which leads to substantial gains in fuel economy,power output and torque.

Accordingly, it is an object of the present invention to provide abolt-on replacement intake manifold for an internal combustion enginethat effectively balances airflow rates across the cylinders of theengines to provide a more efficient fuel burn leading to enhanced fueleconomy, power output, and torque.

It is another object of the present invention to provide an intakemanifold that increases airflow swirl inside the cylinders for a morerobust combustion of fuel.

It is yet another object of the present invention to provide an intakemanifold that does not require a reconfiguration of the enginecompartment.

It is yet another object of the present invention to provide an intakemanifold that is durable, efficient, and seamless with the constitutecomponents of the engine.

In accordance with these and other objects that will become apparenthereinafter, the instant invention will now be described with particularreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view of the prior art intake manifold used on aVolvo D13 diesel engine.

FIG. 2 is a perspective view of one embodiment of the intake manifold ofthe present invention.

FIG. 3 is a top view of one embodiment of the intake manifold of thepresent invention.

FIG. 4 is a bottom view of one embodiment of the intake manifold of thepresent invention.

FIG. 5 is a side view of one embodiment of the intake manifold of thepresent invention.

FIG. 6 is a rear view of one embodiment of the intake manifold of thepresent invention.

FIG. 7 Is a front view of one embodiment of the intake manifold of thepresent invention.

FIG. 8 is a sectional cutaway view of one embodiment of the intakemanifold of the present invention showing the plenum geometry forward ofthe first cylinder runner.

FIG. 9 is a sectional cutaway view of one embodiment of the intakemanifold of the present invention showing the plenum geometry betweenthe third and fourth cylinder runners.

FIG. 10 is a perspective view of one embodiment of the intake manifoldof the present invention showing the interior aspects of the flange

FIG. 11 is a cutaway top view of one embodiment of the intake manifoldof the present invention shown with the plenum removed.

FIG. 12 is a cutaway top view of one embodiment of the intake manifoldof the present invention shown attached to a cylinder head.

FIG. 13 is a close up of the engagement of the runners to the cylinderhead showing the airflow vector angle relative to the cylinder headconduits.

DETAILED DESCRIPTION

FIG. 2 is a perspective view of one embodiment of the intake manifold 1of the present invention. Manifold 1 comprises a plenum 10, a pluralityof runners 11, and a flange 12. The runners 11 are disposedlongitudinally along the plenum 10 extending from and in flowcommunication with the plenum 10, terminating at the flange 12. In thisexemplary embodiment, the manifold 1 includes six runners 11 a, 11 b, 11c, 11,d, 11 e, and 11 f corresponding to each cylinder of a six-cylinderdiesel engine. The flange 12 provides mounting structure to allow theintake manifold 1 to be secured to a cylinder head of an engine, as willbecome more apparent throughout this disclosure. In some embodiments,the plenum 10 includes an inlet port 101 at a first end and defines aninterior space that is configured to receive air from the inlet port 101and distribute it to the runners 11. The inlet port 101, in someembodiments, receives compressed intake air from an intercooler attachedto a turbocharger or a traditional air intake assembly in the case of anaturally aspirated engine. As shown in FIG. 2, the runners 11 havevarying length and curvature relative to the plenum however allterminate at the flange 12 at the same elevation. The runners 11 arealso tapered, i.e. narrow down, from the plenum to the flange 12.

FIGS. 3 and 4 are respective top and bottom views of the intake manifold1 in isolation. Here it can be seen that the plenum 10 has a generallyasymmetrical shape that initially widens from the inlet 101 to the firstrunner 11 a and then narrows or tapers down in width from the firstrunner 11 a to its terminal end 103. As shown, the width of the plenumis largest adjacent to the first runner 11 a and smallest adjacent tothe last or sixth runner 11 f. Further, starting at third runner 11 cand moving toward sixth runner 11 f, the length of each runnerincreases. As the length of each successive runner increases from runner11 c to 11 f, the curvature also increases, with the longest runner,sixth runner 11 f, having the largest curvature. For purposes offitment, first and second runners 11 a and 11 b are shorter in lengththan the rest of the runners, with second runner 11 b being theshortest.

The curvature and profile of the plenum 10 is defined by a concave topsurface 104 that curves inward toward the center of the plenum 10 and aconvex bottom surface 105 of the plenum 10 that curves away from thecenter of the plenum 10. From the inlet 101, the plenum 10 initiallywidens toward the first runner 11 a and then gradually narrows towardthe terminal end 103. This profile, in combination with the otherfeatures of the invention, provides optimal airflow characteristics, asfurther described. Optionally provided is an auxiliary air inlet 102which may be connected to an exhaust line to provide for recirculationof fuel-containing exhaust gases effective for lowering the emissions ofthe engine.

FIG. 5 is a side view of the manifold 1 shown from the aspect of the topsurface 104 of the plenum 10. FIG. 6 is a rear view of the manifold 1.Here it can be seen that the bottom surface 105 of the plenum 10 iswider than the top surface 104, i.e. the plenum narrows from the bottom105 to the top surface 104. This narrowing allows for the creation ofhigh pressure zones toward the top surface 104 and low pressure zonestoward the bottom surface 105, which creates a pressure differentialthat forces air into the runners 11 in order to optimize and balance airflow across the runners. FIG. 7 is a front view of the manifold 1 alsoshowing the generally wide bottom surface 105 as compared to the topsurface 104.

FIGS. 8 and 9 show cutaway perspective views of the manifold 1 at twolocations along the length of the plenum 10. FIG. 8 shows thecross-sectional geometry of the plenum 10 at a location just forward ofthe first runner 11 a. Here, the cross-section of the plenum 10 has agenerally rounded triangular profile, again narrower at the top surface104 and wider at the bottom 105 promoting a pressure differential insidethe plenum 10. FIG. 9 shows the cross-sectional geometry of the plenum10 at a location at a halfway point along the length of the plenum 10,i.e. between the third and fourth runners 11. Here, the cross-sectionalso has a generally rounded triangular profile similar to the profileshown in FIG. 8 except that the cross-section surface area at this pointis larger than that shown in FIG. 8. Moving away from the cross-sectionshown in FIG. 9 toward the terminal end 103, the surface area willdecrease in accordance with the tapered shape of the plenum 10. Thesecharacteristics are consistent with the overall plenum shape thatgradually increases in size from the inlet 101 to the first runner 11 aand then begins to decrease toward terminal end 103. Said succinctly,the plenum generally narrows from first runner 11 a toward the lastrunner 11 f and generally narrows from bottom to top.

FIG. 10 is a cutaway perspective view showing the flange side of themanifold 1 and in particular the underside of the flange 12 thereof. Asshown, the flange 12 includes a plurality of ports 121 aligned and inflow communication with the runners 11 of the manifold 1. In someembodiments, disposed around each port 121 is an O-ring 122 thatprovides a seal between the flange and the cylinder head (not pictured).In some embodiments, the ports 121 are smaller than the intake conduits21 on the cylinder head of a given motor (See FIG. 12), which serves tofocus the airflow from the runners at the centerline thereof to optimizeairflow and efficiency.

FIG. 11 is another perspective view of the manifold 1 of the inventionshown here with most of the plenum 10 removed from view. Here, thebottom surface 105 of the plenum is exposed to show the interior aspectsof the runners 11. It can be seen that the interior of the runners 11are circumferentially radiused at the junction between the bottomsurface 105 and the runners 11. This radiusing removes any abruptgeometry from the inside of the manifold 1 in an effort to smooth outairflow within the manifold 1.

FIG. 12 is a top view of one embodiment of the manifold 1 secured to anexemplary cylinder head 20. The cylinder head has a plurality ofconduits 21 that are in flow communication with a respective runner 11.In some embodiments, the conduits 21 are angled with respect to the headin order to match the particular geometry of the engine cylinders withinthe engine block. The conduits 21 feed into the cylinders of the engineto introduce air therein for compression and eventual ignition of fuelby way of heat of compression. Here it can be seen that, in someembodiments, the runners 11 are narrower than the conduits 21 which iseffective for directing airflow exiting the runners to the problemangle. With reference to close-up FIG. 13, the runners 11 are each sizedand curved such that the angle A of the resultant airflow vector Vexisting each runner 11 and entering each conduit 21 of the cylinderhead relative to the centerline of the conduits 21 is substantiallyequal. In other words, the arrangement of the intake manifold 1 is suchthat air exits each runner 11 at substantially the same angle. In someembodiments, with particular application to the Volvo D13 diesel enginehead, the optimal angle A of the airflow vector V is 11 degrees, whichmatches the angles of the ports 21 incident to the cylinder head 20. Inthe particular embodiment shown in FIG. 12, this is accomplished byshaping the runners 11 c-11 f such that the longer the runner length,the greater the curvature thereof, providing the ideal “line of sight”of air from the plenum into the runners and down into the cylinder head.The first runner 11 a is slightly longer than the second runner 11 b inorder to accommodate the geometry of the plenum 10 while maintaining theideal airflow vector angle.

The intake manifold 1 of the present invention provides substantialincreases in power and overall fuel economy primary by balancing theairflow to each cylinder of the engine that otherwise is not possiblewith the traditional “shoe box” design. More specifically, the wideningof the plenum just past the inlet 101 actually slows down the airflowsomewhat to allow sufficient air to enter the first and second runners11 a and 11 b. This solves the problem in the traditional design whereair races past the first few cylinders and collects at the closed rearend of the plenum, causing an uneven mixture of fuel and air among thecylinders. After the initial widening of the plenum, the plenum tapersdown in width that, in combination with incrementally increasing runnerlength, balances and optimizes the airflow across each cylinder andprovides the optimum air exit angle. Additionally, the pressuredifferential created by the widening of the plenum 10 from the topsurface 104 to the bottom surface 105 will tend to force air into therunners from the top down, increasing and balancing airflow to therunners and eventually to the cylinders. Moreover, the geometry of themanifold 1 and the angle at which air exist the runners and enters thecylinder head causes a substantial increase in “swirl” of air into thecylinders, which causes a more even distribution of vaporized fuel ineach cylinder therefore providing more robust combustion.

With this significantly more balanced airflow and increased swirl, thefuel/air mixture in each cylinder is more consistentcylinder-to-cylinder, providing for a cleaner and more efficient fuelburn which greatly enhances efficiency, power, and torque of the enginewhile also lowering carbon emissions. Additional benefits includeincreased engine and drivetrain life as the cylinders run more evenly,providing even power to the driveshaft. Indeed, the intake manifold ofthe present invention has demonstrated a 6-7% increase in fuel economysimply when bolted-on as a replacement for the standard manifold foundon a Volvo D13 motor, i.e. without tuning.

It is appreciated that the present invention has been described inexemplary fashion with reference to the drawings appended hereto. Theintake manifold 1 is not limited to application for a particular engineor type of engine but rather the design considerations can be carriedthrough to any engine application including diesel, gasoline, flex fuel,alternative fuel, or the like. While the relative dimensions are notlimiting in any respect, it is useful to provide some examples. In oneembodiment, the length of the runners are as follows: first runner 11 a—7.182″, second runner 11 b —7.005″, third runner 11 c —7.629″, fourthrunner 11 d—8.857″, fifth runner 11 e —10.597″, and sixth runner 11 f—12.574″. In one embodiment, the runners taper in cross sectional areafrom 4.242 square inches at the plenum 10 to 3.597 square inches at theflange 12. It is certainly appreciated and understood that suchdimensions can vary based on design and application considerationswithout departing from the spirit and scope of this invention. It isalso appreciate that, in some embodiments, the runners 11 need notextend straight out from the plenum 10, but rather can be bent or curvedat certain angles to match the geometry of an engine compartment. Forexample, the runners 11 could be bent such that the flange 12 isperpendicular to the bottom surface 105 of the plenum while theremaining design considerations remain intact to provide optimal airflow and air exit angles into the cylinder head.

The instant invention has been shown and described herein in what isconsidered to be the most practical and preferred embodiments. It isrecognized, however, that departures may be made therefrom within thescope of the invention and that obvious modifications will occur to aperson skilled in the art.

What is claimed is:
 1. An intake manifold, comprising: an asymmetricalplenum having a first end including an inlet, a closed terminal end, atop surface and a bottom surface; a flange; a plurality of runnersextending from said bottom surface of said plenum and terminating atsaid flange; said plenum defining an interior space in flowcommunication with said runners; wherein, in profile, said top surfaceis concave, curving inward toward a center of said plenum and saidbottom surface is convex, curving away from said center of said plenum;wherein said interior space of said plenum is configured such that avector angle of air exiting each of said plurality of runners are thesame.
 2. The intake manifold of claim 1, wherein said each of saidplurality of runners taper down from said plenum to said flange.
 3. Theintake manifold of claim 1, wherein an interior aspect of each of saidplurality of runners at said bottom surface is radiused.
 4. The intakemanifold of claim 1, wherein said intake manifold is configured to beattached to a cylinder head at said flange, placing each of saidplurality of runners in flow communication with a respective conduit ofsaid cylinder head.
 5. The intake manifold of claim 1, wherein each ofsaid plurality of runners has a different length.
 6. The intake manifoldof claim 1, wherein each of said plurality of runners is curved.